The present disclosure relates generally to pipe gripping assemblies, and more particularly to self-aligning pipe gripping pistons.
The process of drilling an oil well typically involves assembling drill strings and casing strings and inserting the drill strings and casing strings into the ground to form a well bore. The drill strings and casing strings extend downward from an oil drilling rig and into the ground. The drilling strings and the casing strings are rotationally driven into the ground by a top drive motor on the drilling rig. Drill strings typically include a series of drill segments that are threaded together. The lowest drill segment (i.e., the drill segment extending the furthest into the ground) includes a drill bit at its lower end. Typically, the casing string is provided around the drill string to line the well bore after the drilling operation has been completed. The casing string is configured to ensure the integrity of the well bore. The casing string includes a series of casing segments that are threaded together.
Recently, pipe gripping devices have been devised that utilize the existing top drive of the oil drilling rig to assemble the drill strings and the casing strings. Some conventional pipe gripping devices are fixedly mounted in a robust support. When such conventional gripping devices are subject to a large off-center force during operation, however, the conventional gripping device may become damaged, which is both costly and time consuming as the drilling operation must cease in order to repair the damaged pipe gripping device.